A former OZ mobile suit pilot, Karl later became the test pilot of Gundam Lucifer during its test run. However, the ZERO System 2.0 proved unstable and drove Karl mad. This is what caused Karl Noembreux to run away with Gundam Lucifer, believing he could bring peace by eliminating war-like parties. Eventually he encountered his younger sister Tiel, who had lead an elaborate chase to find him. Unfortunately, Karl was beyond aid at this point, and when his sister refused to help carry out his mad plan, He attacked, and the two siblings both fell into the Earth's atmosphere.